(CBS) -- With enough exposure carbon monoxide can be deadly. We saw that last month in an Oak Brook home where one man died and seven women were sickened after a CO leak. When firefighters got there, levels were already at 1,000 parts per million.
That's why having a CO detector in your home is vital, but will yours work when you need it? CBS 2's Chris Martinez put 10 detectors to the test.
Inside her home, Gina Corso first felt it, she said on Tuesday, with the headaches and the nausea building every hour.
"Wednesday morning I woke up and my headache was worse than it was the first day. But this time I had the body aches," Corso said.
She thought it was the flu, until it reached her dad.
"He had passed out in the basement," Corso remembered.
The odorless, colorless cause was revealed in the ER.
"They hooked me up to oxygen right away, started all the blood tests and that's when they found out it was carbon monoxide in the system," said Corso.
The source was her furnace. It was in the same room as her carbon monoxide detector. She showed us that it was "hangin' right here on this screw." It never went off.
"I would never have known," said Corso.
UL approved CO alarms are required to sound within 15 minutes if levels reach higher than 400 parts per million.
So we gathered 10 detectors. One was brand new. Nine others were gathered as is from volunteers, including Corso.
We checked the batteries and then did a non-scientific test, using car exhaust to generate the CO.
Our reading right now is what? "Zero," said Carol Stream firefighter Chris Diebold. He used his meter to help us track the levels.
"433," said Diebold.
And we got nothing.
"Nothing," said Diebold.
They climbed fast.
"Every one of these should be activated," said Diebold.
Then finally, "I've got one of these going off," said Diebold.
Then the next, "I got another one going off," said Diebold.
But in all, only three alarms including the new one met the standard, sounding within 15 minutes. Our test continued.
"And there are some that aren't even activated yet," said Diebold.
The next four, including Corso's not sounding until at least 40 minutes later.
"I'm very surprised by this. Yes," said Diebold.
After CO levels were high enough to kill us if we were exposed for a little more than an hour.
"It's been a very long time since I've seen 1,000 parts per million," said Diebold.
Worse yet the final three never went off.
That means three met the standard and four went off too late. Three never went off at all.
At levels over 1,000 parts per million and without a working CO detector in your home Deputy Fire Chief Bob Hoff warns that "you're probably not gonna survive."
It's a beyond scary thought for Kim Koblitz who owns one of the three that never went off.
"You buy them on per say the assumption that they're going to do their job and obviously it doesn't," Koblitz said.
So why didn't some of these work? Age is a factor.
Out of the seven that never went off or went off late, five were at least 14-years-old. Two were at least seven-years-old. Fire officials say you should replace yours every 3 to 5 years.
Newer models have an alert built in that will tell you when it needs to be replaced. Just because you press the button and it beeps does not mean the sensor is working.
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